north polar sequence
(NPS)
(set of stars previously used to define magnitudes)
The north polar sequence (NPS) is a selected set of stars for
calibrating magnitudes, used before the adoption of the
UBV photometric system. The selected stars were all close to
the celestial north pole (within about two degrees), making them
observable on any (clear) night from northern-hemisphere sites,
convenient for calibration of other observations. The set numbered
roughly a hundred stars at its largest, having been enlarged over
time.
(stars)
Further reading:
https://en.wikipedia.org/wiki/North_polar_sequence
http://ui.adsabs.harvard.edu/abs/1917AnHar..71...47L/abstract
Coordinates: | NPS J1202+8926 |
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Index